The present invention pertains to vibratory plates of the type used in various construction activities to tamp and compact soil and other loose base materials. A typical vibratory plate construction includes a flat, ground-engaging plate made of steel or other strong and rigid material. The plate is attached to an overlying frame and separated therefrom by elastomer shock mounts, typically two shock mounts near the front edge of the plate and two mounts near the rear edge of the plate. The prior art teaches a variety of orientations for the shock mounts depending on the properties of the elastomer material that are used to optimize vibratory compaction.
The frame carries an engine and the plate carries a rotary vibratory exciter connected to the engine by a drive belt. Vibratory plates may be uni-directional or bi-directional (reversible), but the present invention relates particularly to single direction vibratory plates. The driven exciter imparts vibratory forces to the plate and the underlying surface material being compacted. In a single direction vibratory plate, the exciter is typically mounted toward the front of the plate to maximize the amplitude of the vibratory forces and to facilitate forward movement of the plate. The prior art shows many different arrangements in the positioning of elastomeric shock mounts on vibratory plates, but often with no discussion as to how operation of the shock mounts in shear or compression can be utilized to optimize performance.